My taboo has been sounding really good but it has developed a noisy background problem that sounds like hash or static. I'v changed the tubes and pulled the preamp tube and the problem still persists.

I'v observed that it sounds noisier when the feedback knobs are fully to the left as well and the noise persists at all volume levels but it doesn't appear when turned on until the tubes have come up to speed.

The only thing that I think I might have done is use an rca 5v4 rectifier tube....

I get static only when I turn the feedback knobs. I know it's not much help, but maybe it has something to do with the feedback adjustment. I would like to know, if you find out from Steve, what is causing it.

Yep, that's the problem I've had from the get go. I immediately notified Steve, and he sent me a new set of tubes...didn't work. I sent it back for a replacement....same issue.

Steve told me that after checking the one I sent back he found nothing wrong with it?! ???

So I tried the following:

Adding a extra 3 prong adapter to the power plug to raise the distance between the plug and my power strip to help with potential ground loop feedback...no dice.

Spraying detox it on and into the feedback knobs...nice try.

Changing all of the tubes 3x over...give me a break.

Anyway no one has been able to give me a good answer or solution but it appears to have something to do with the feedback knobs and buildup of static. After about an hour or so it goes away so if you can live with this I would probably let it be.

As you can tell I am fairly clueless as to the inner workings of electronics, but if anybody has any suggestions I'm open!

Well I'v played with my taboo with no improved success. I'm beginning to wonder if a cap or resister might be causing the problem and am thinking of opening up and taking a look. Given the hash noise coming from both channels, are there any suggestions on what I should focus on???

1. The first thing you should do is replace all the tubes with new ones.2. Take the amp to a friends house and try it out there with a different source, preamp, and speakers.3. Open the TABOO and place a tempororay jumper wire accross the volume pot to essentially bypass it (full volume)and use a preamp or some source with a volume control. If the noise is gone, the volume pot in the TABOO is bad. 4. Send it to Decware for diagnosis

I have a possible explanation. Possible because I have not been able to reproduce what you guys are talking about in over 2 months of trying...

The Taboo was named such because it twists the rules pretty hard when it comes to conventional amplifier design.

The Taboo has outputs and a feedback network that float above ground. This means the output/feedback network are always in a constant search mode for ground. That means that speaker wires can become somewhat of an antenna. Changing speakers wires could effect the problem you describe.

If you ground the negative or positive speaker post to the chassis in any way, you would hear the amp get 3 times louder and then most likely fall flat on it's face. With this in mind, I can see where having speaker cables on the floor could induce static from the carpet into the feedback network.

I can also see where certain loudspeakers could even change this. You might try changing the loudspeaker(s) the next time it happens and see if it goes away. Another thing that you could try is to turn off the amp for a few minutes and then turn it back on, sort of like a reboot.

I would say with this amp it is probably more important then most to have the speaker connections completely tight and clean at all times, same thing at the amp.

just wanted to let folks know that steve was right on(obviously, and at least in my case) with his diagnosis. last night one channel became significantly lower than the other. oh, i own a taboo and a bottlehead foreplay pre. this was on both cd and vinyl. i swapped out tubes and ic's on both units, and then switched speaker cables to rule out speaker problems. could not find the culprit. speaker cables (bare silver ends) were tightly bolted down on the taboo. i then ruled out the foreplay when i ran the cd straight through the taboo and the problem persisted. i was just about to disconnect everything to either send the taboo back, or bring it in to a local tech when i read steve's post. i noticed that i had experienced a pretty dramatic increase in volume, so i slowly started to twist the left black speaker post, and immedetely the lost sound was recovered. this was not a case of the connection being loose. this seemed to be more of a grounding issue. in any event, if you own a taboo and your sound gets comprimised in any way, i would recommend you re reead steve's post and make sure all those connections are good. and even if they seem to be, keep fiddling with them.